Search Results (2,974)

The occurrence of marine heatwaves (MHWs) and phytoplankton blooms is accelerating under climate change, yet the frequency and drivers of their compound co-occurrence remain poorly understood. Using coastal-optimized satellite observations from 2003–2020, we mapped global compound MHW–phytoplankton bloom (MHW-PB) events across coastal large marine ecosystems and quantified their spatiotemporal trends and environmental predictors. Compound events are increasing at 4.8% yr⁻¹, driven primarily by a 6.5% yr⁻¹ rise in MHW frequency; a temporal shuffle test confirms this trend falls below random co-occurrence expectation, indicating biological suppression actively constrains compound event growth. The compound independence factor (CIF) reveals latitudinal heterogeneity: low-latitude upwelling systems show MHW–PB mutual exclusivity, while high-latitude and eutrophic coastal regions show positive co-occurrence tendency. Interpretable machine learning further shows that nutrient availability dominates bloom responses at low latitudes whereas light dominates at high latitudes, with MHW intensity exhibiting nutrient-dependent non-linear associations with bloom probability. Paradoxically, compound frequency accelerates nearly twice as fast in low latitudes (6.1% yr⁻¹) as in high latitudes (3.5% yr⁻¹), driven by rapid tropical MHW acceleration. These diverging regimes signal dual ecological risks: trophic mismatches in upwelling systems and escalating hypoxia and harmful algal bloom hazards in eutrophic coastal waters. Full article

This study conducts a cradle-to-gate Environmental Life Cycle Assessment (E-LCA) of tea production in Sri Lanka, comparing smallholder and estate-owned plantations processed by Orthodox and Crush–Tear–Curl (CTC) methods. Unlike most tea LCA studies that treat cultivation as a single undifferentiated phase, this work explicitly incorporates the perennial nature of tea by using a modular life cycle framework that separates the agronomic stages alongside factory processing up to the packed-tea gate. This approach allows a more precise allocation of long-term environmental burdens over the entire productive lifespan of the tea plant, addressing a methodological gap in the literature. Four production scenarios were evaluated: Smallholder-Orthodox, Smallholder-CTC, Estate-Orthodox, and Estate-CTC, with the functional unit set to 1 tonne of processed tea. Primary data were gathered through structured surveys of 30 plantations (25 smallholders, 5 estates) and 5 tea factories, supplemented by secondary data from Ecoinvent v3.11 and national statistics. The CML-IA Baseline method in SimaPro v9.5 was applied to characterize impacts across eight impact categories: global warming potential (GWP), abiotic element depletion, fossil fuel depletion, acidification, human toxicity, terrestrial ecotoxicity, freshwater ecotoxicity, and eutrophication. Results indicate that Smallholder-Orthodox systems have the highest GWP (3304 kg CO₂ eq per tonne), whereas Estate-CTC systems show a lower GWP (2894.87 kg CO₂ eq). Acidification potential ranges from 47.21 kg SO₂ eq for Smallholder-Orthodox to 41.25 kg SO₂ eq for Estate-CTC. Overall, the findings suggest that the scale of plantation management has a greater impact on environmental performance than processing technology, highlighting the need to focus sustainable practices on the cultivation stage, exactly where the perennial crop modeling approach used here provides the greatest analytical benefit. Full article

Over the past two decades, Citizen Science (CS) has experienced rapid growth, driven by technological advancements and the rise of digital platforms. This work examines the necessity for standardization in Citizen Science data management and discusses how existing data standards can enhance the impact of citizen-generated data. CS standardization ensures data quality, comparability, reusability, and interoperability, making data suitable for contributing to the Marine Strategy Framework Directive (MSFD) and the United Nations Sustainable Development Goals (SDGs). This paper examined 130 Citizen Science publications and found that most collected data referred to the MSFD Descriptor 1 (Biodiversity—44.96%) and Descriptor 10 (Marine Litter—20.93%), followed by the alien species distribution (D2—11.63%), hydrography (D7—6.20%), eutrophication (D5—6.20%), and marine pollution (D8—3.10%). Analysis of 108 publications on SDG alignment revealed that the majority (35.58%) focused on reducing marine pollution. This paper reviews the best practices for effective Citizen Science data management, including standards for data structures, content, values, and exchange. Based on this review, Darwin Core, Ecological Metadata Language (EML), and the OGC SensorThings API appear to be the most suitable standards for MSFD-relevant CS data. Therefore, policymakers could enable the formal integration of standardized CS datasets into MSFD monitoring workflows. Full article

Excessive phosphorus discharge from aquaculture effluent significantly contributes to coastal eutrophication, while conventional adsorbents exhibit limited phosphorus removal efficiency in high-salinity, weakly alkaline seawater effluent. This study developed iron/calcium co-modified chlorella biochar (FCBC) through co-impregnation and high-temperature pyrolysis, optimizing the preparation process via the Box–Behnken response surface method. The optimal conditions were identified as an iron concentration of 2.5 mol/L, a calcium concentration of 2.0 mol/L, a pyrolysis temperature of 717 °C, and a duration of 113 min. Under these conditions, FCBC achieved a phosphorus removal rate of 93.23% within 3 h, which was significantly higher than that of the unmodified Chlorella biochar (BC, <8% within the same reaction time). The Fe/Ca co-modification endowed FCBC with a positively charged surface, an increased average pore size of 22.773 nm, and good magnetic responsiveness (saturation magnetization of 6.68 emu·g⁻¹). FCBC demonstrated remarkable adaptability, achieving over 97% phosphorus removal across a pH range of 3 to 11, salinity levels of 5 to 40‰, and phosphorus concentrations of 1 to 15 mg/L. Its adsorption kinetics conformed to pseudo-second-order kinetics (R² = 0.987) and the Freundlich model (R² = 0.971), with efficient phosphorus removal primarily attributed to iron–calcium synergistic effects. FCBC presents significant potential for phosphorus treatment in marine aquaculture effluents. Full article

Deposit-feeding aquatic oligochaete worms are abundant and widely distributed benthic animals in lakes that affect the nutrient cycling between sediments and the water and thus the water quality. This effect can be density-dependent and affected by the presence of filter-feeding bivalves, which can modulate the worms’ impact. We conducted a mesocosm experiment with high, medium, and low densities of the tubificid worms Limnodrilus hoffmeisteri (Oligocheata, Tubificida, and Naididae) in the presence of the filter-feeding bivalve Hyriopsis cumingii. In the low-density treatment, the concentrations of nitrate nitrogen (NO₃⁻-N), ammonium nitrogen (NH₄⁺-N), and organic suspended solids (OSSs) increased moderately compared with the control. In the medium- and high-density treatments, there were also increases in total nitrogen (TN), total phosphorus (TP), soluble reactive phosphorus (SRP), total suspended solid (TSS) and inorganic suspended solid (ISS) concentrations. Moreover, the biomass of phytoplankton (Chl a), the light attenuation coefficients, and the abundance of both cladoceran and rotifer zooplankton rose with increasing worm densities. Water quality deteriorated in both the medium and high worm density treatments, likely due to increased nutrient leading to an increase in the biomass of phytoplankton in our mesocosms, even though plankton-consuming bivalves were present. Thus, during the restoration of eutrophic shallow lakes with a high density of worms, more bivalves are needed to compensate for the negative impact of worms on water quality. Full article

Cascade reservoirs on the Drina River (Bosnia and Herzegovina) are heavily modified water bodies that require reliable biological tools for assessing trophic status and ecological potential. Under the Water Framework Directive (WFD), assessments of surface water ecological status and potential rely on biological quality elements, since aquatic communities integrate and respond to prevailing environmental conditions and thus serve as reliable indicators of water quality. This study aims to (i) describe phytoplankton diversity, biomass, and functional-group composition along the Drina reservoir cascade, (ii) examine monthly changes across the studied reservoirs, (iii) determine trophic status and ecological potential, and (iv) provide a preliminary estimate of total phosphorus thresholds that may support future setting of ecological potential boundaries. Phytoplankton composition and functional groups were analysed in three longitudinally connected reservoirs of the Drina River during four monthly surveys in 2024. A total of 80 phytoplankton taxa were recorded, with diatoms dominating most of the study period. The highest biomasses were recorded for Fragilaria crotonensis, Dinobryon divergens, Acanthoceras zachariasii and Sphaerocystis sp., while the dominant functional groups were P, E, A, and F. Phytoplankton assemblage structure showed moderate spatial differentiation among the reservoirs. Mean chlorophyll a and Carlson’s Trophic State Index indicated eutrophic conditions in the Višegrad Reservoir and mesotrophic conditions in the Perućac and Zvornik reservoirs, while biomass showed a pronounced summer maximum, particularly in Perućac. Ecological potential was generally classified as good or better, except for a moderate classification in the Zvornik Reservoir in late summer. The good/moderate TP boundary was estimated at 39 µg L⁻¹, linking EQR-based ecological assessment with the onset of eutrophic conditions. Overall, this study represents the first application of the phytoplankton functional group approach in cascade reservoirs in Bosnia and Herzegovina and may provide a valuable basis for the development of a phytoplankton-based monitoring framework in lakes and reservoirs, which is currently lacking. Full article

The aim of this paper is to identify the major environmental impact categories associated with geotechnical works, evaluate the adequacy of commonly used weighting methods, and highlight the need to adapt them to sector-specific characteristics and local conditions. Currently applied weighting approaches rely on standardized values that may not accurately reflect the environmental impact of activities across different economic sectors. Moreover, several impact categories, such as eutrophication, acidification, and water use, are strongly dependent on local conditions. The study included the identification of key environmental challenges across Europe and the development of maps illustrating their spatial distribution. Four weighting methods were applied and compared in terms of their influence on the ranking of assessed materials. The analysis shows that geotechnical works include Global Warming Potential, Photochemical Ozone Creation Potential, Particulate Matter, and Abiotic Depletion Potential—fossil. Adapting weightings to local conditions did not change the ranking of analyzed materials in Poland. However, it may significantly influence the results in regions facing different environmental challenges. The results may support the adaptation of environmental assessment methods in geotechnics and contribute to informed decision-making for sustainable development. Full article

Microalgae and cyanobacteria are photosynthetic microorganisms capable of removing nutrients from eutrophic waters and producing biomass. Therefore, the aim of this study was to evaluate the bioremediation performance of three microalgae and one cyanobacterium native to Lake Xochimilco and to assess their potential for biofuel production (biodiesel and biogas) from biomass generated. In photobioreactors, ammonium (96.61–97.06%), nitrate (82.4–100%), and phosphate (83.95–89.71%) were effectively removed from the lake water. The specific growth rates ranged from 0.041 to 0.144 d⁻¹ and biomass productivities from 0.016 to 0.049 g L⁻¹ d⁻¹, with high biomass yield on the substrate. The estimated CO₂ fixation rates ranged from 0.024 to 0.092 g L⁻¹ d⁻¹. Chlorella sp. achieved the highest yield of fatty acid methyl esters (FAMEs) with 91.24% of the extracted lipids. Overall, saturated FAMEs were predominant in the biodiesel; however, the presence of monounsaturated FAMEs such as methyl palmitoleate and methyl oleate enhances their fluidity and oxidative stability. Synechocystis sp. and Chlorella sp. produced the most biogas using biomass after lipid extraction, at 429.5 L kg⁻¹ VS and 404.9 L kg⁻¹ VS, respectively, with over 60% biomethane. These strains represent a sustainable and promising possibility for water bioremediation and generating biofuels. Full article

The main scope of the present study is to assess the environmental and economic outcomes of applying distinct Climate-Smart Agricultural (CSA) practices in apple cultivation. Thus, four different CSA practices, including organic farming, cover crops, floral bands, and grazing, were selected, and their environmental and economic performance was evaluated and compared to that of a conventional apple orchard system (baseline). Specifically, Life Cycle Assessment (LCA) and Life Cycle Costing (LCC) methodologies were applied to assess the environmental and economic sustainability of the studied systems, respectively. Among the studied practices, grazing exhibited the best environmental performance among the modeled scenarios (approximately 25% decrease in greenhouse gas emissions compared to the baseline under the assumed conditions), followed by organic farming that significantly decreased eutrophication- and ecotoxicity-related impacts. Similarly, organic farming and grazing exhibited the best economic performance in the concept of the present study, with the total profit per hectare rising to approximately 5300 € and 4300 €, respectively, compared to the value of 3700 € of the conventional apple orchard. The results suggest that the implementation of CSA practices has the potential to improve the environmental and economic performance of apple orchards under the modeled conditions. Full article

This study investigates the impacts of algogenic organic matter (AOM) distribution characteristics, specifically molecular weight (MW) and hydrophobicity, on the formation of disinfection byproducts (DBPs) derived from Microcystis aeruginosa. This study focuses on both extracellular organic matter (EOM) and intracellular organic matter (IOM) and their contributions to DBP formation. AOM was divided into 12 fractions based on MW and hydrophobicity (transphilic, hydrophilic, and hydrophobic fractions). The results reveal that the hydrophobic fraction (HPO) contributes the most to IOM, while low-MW (<1 kDa) and high-MW (>100 kDa) organic matter are the main components of AOM. An analysis of fluorescent species indicates that humic acid-like and fulvic acid-like compounds derived from the hydrophilic fraction (HPI) of EOM and the hydrophobic fraction (HPO) of IOM are the dominant low-MW (<1 kDa) species. Additionally, aromatic proteins derived from HPO in both EOM and IOM are the dominant high-MW (>100 kDa) fluorescent species. This suggests that proteins or polysaccharides are the primary adsorbents on the membrane during ultrafiltration (UF), while the humic acid component is not significantly deposited. Furthermore, this study identifies that the >100 kDa HPO in IOM serves as the main precursor for trichloromethane (TCM), trichloroacetic acid (TCAA), and dichloroacetic acid (DCAA). In EOM, the precursor for the highest TCMFP (63.6 µg/mg-C) is the >100 kDa HPI, while the highest contribution to TCM (21%) is from the >100 kDa HPO. These findings provide crucial information for controlling DBPs derived from AOM through membrane filtration, particularly in eutrophic water environments. Full article

Lake Erhai is an important plateau freshwater lake in China. It serves not only as a crucial drinking water source for the local region but also as the core area of the Cangshan Erhai National Nature Reserve. Consequently, Lake Erhai plays an extremely significant role in the local economy, society, and ecology. Since 2000, the water quality of Lake Erhai has continuously deteriorated, showing a eutrophic trend. To identify the primary driving forces behind these water quality changes, this study employed stepwise regression analysis. Climate conditions, socio-economic development within the basin, and implementation of environmental protection measures (IEPMs) were considered influencing factors for a comprehensive and systematic analysis of Lake Erhai’s water quality. The results indicate that rising air temperature may increase total phosphorus (TP) concentration, while rainfall may elevate both TP and total nitrogen (TN) levels. In contrast, higher wind speed may reduce chemical oxygen demand (COD_Mn), TP, and TN concentrations. Socio-economic development, meanwhile, may contribute to increased COD_Mn concentration. Based on these findings, this paper proposes recommendations focusing on formulating more effective non-point source pollution control measures and strengthening water quality monitoring in Lake Erhai during summer. By identifying the key natural and anthropogenic drivers of water quality changes in Lake Erhai, this study provides a scientific basis for the development of targeted pollution control strategies and directly contributes to the protection of clean water sources. Moreover, its revelation of the coupled impacts of climate change and socio-economic activities enhances understanding of plateau lake ecosystem resilience. This insight is critical for ensuring regional ecological security and serves as a model for advancing sustainable development goals in similar lake systems worldwide. Full article

Phosphorus is an essential and finite resource critical for global food production, yet its inefficient use and discharge from wastewater systems contribute to eutrophication and resource depletion. The transition from conventional wastewater treatment plants to water resource recovery facilities has intensified interest in technologies that enable phosphorus recovery within a circular economy framework. This review provides a critical and up-to-date synthesis of phosphorus recovery strategies from wastewater, with primary emphasis on struvite (MgNH₄PO₄·6H₂O) crystallization as one of the most mature and practically implemented recovery routes. The occurrence and chemical forms of phosphorus in wastewater streams are discussed alongside conventional approaches, such as enhanced biological phosphorus removal and chemical precipitation, in order to position struvite recovery within the broader phosphorus management landscape. In addition to struvite crystallization, selected competing and complementary recovery pathways, including electrochemical systems, biochar-assisted processes, and sludge ash recovery, are discussed to compare technological maturity, recovery potential, and practical applicability. Particular attention is given to reactor configurations, full-scale applications, and commercial technologies to assess operational reliability, recovery performance, and fertilizer product quality. Life-cycle assessment results and regulatory developments are also discussed to contextualize sustainability claims, technology selection, and market integration. The review identifies key technical and economic challenges, particularly regarding magnesium supply, competing ions, wastewater matrix effects, and the feasibility of mainstream application. Overall, controlled sidestream struvite crystallization appears to offer the most favorable balance between recovery efficiency, operational reliability, and fertilizer product quality under suitable plant conditions. Full article

Global freshwater resources face severe water quality degradation, with chlorophyll-a (Chl-a) concentration serving as a critical eutrophication indicator. While deep learning methods enable accurate Chl-a retrieval from remote sensing reflectance (Rrs) spectra, the scarcity of paired Rrs-Chl-a samples limits model generalization and causes overfitting, particularly in optically complex inland waters. To address this data bottleneck, we propose a physics-constrained latent diffusion model for synthesizing high-fidelity paired Rrs-Chl-a data to augment limited training sets for deep learning-based water quality retrieval. Our framework integrates three key innovations: (1) a lightweight variational autoencoder achieving 8.6:1 latent space compression, reducing computational overhead while preserving spectral features; (2) band-selective attention mechanisms targeting chlorophyll-sensitive wavelengths (440, 550, 680, and 700–750 nm) based on bio-optical principles; and (3) physics-guided conditional encoding that captures concentration-dependent spectral responses across oligotrophic to eutrophic regimes. Evaluated on the GLORIA dataset, our model demonstrates superior performance in spectral similarity (0.535), sample diversity (0.072), and distribution matching (Fréchet distance 0.0008) compared to conventional generative models. When applied to data augmentation, synthetic spectra improved downstream Chl-a retrieval from R²= 0.75 to 0.91, reducing RMSE by 39%. This physics-informed generative approach addresses data scarcity in aquatic remote sensing research, supporting global needs for enhanced understanding of inland and coastal water quality dynamics in data-limited regions. Full article

Eutrophication caused by excessive nitrogen and phosphorus input remains the most severe environmental threat to the Baltic Sea. While nutrient sources in general are widely studied and regulated, the relative importance of maritime nutrient inputs and their regulatory treatment remain insufficiently integrated into land-based nutrient assessments. This study applies a load-based source apportionment approach and quantifies the maritime- and port-related nutrient inputs to a Baltic Sea coastal system, in relation to other nutrient contributors (riverine, municipal, and industrial sources). Additionally, the stringency of the regulatory frameworks governing each source is assessed using a qualitative regulatory classification scale and compared to the proportion of each nutrient source. The results show that riverine inputs dominate total nutrient loading, accounting for over 90% of both nitrogen and phosphorus. Maritime sources contribute only a small share overall. However, fertilizer cargo handling constitutes the largest nitrogen point source, while ship wastewater inputs are negligible. In contrast, ship wastewater is subject to the strictest regulatory controls, whereas fertilizer handling operates under permits lacking explicit nutrient discharge limits. The findings reveal a governance mismatch between nutrient pressures and regulatory focus and highlight the need to better align nutrient management priorities with actual environmental pressures in semi-enclosed seas. Full article

Phosphorus release from sediments significantly influences eutrophication in shallow lakes; however, its dynamics in drawdown zones under alternating inundation and drying cycles remain understudied. This study investigates the mechanisms of phosphorus release from sediments in the drawdown zone of Nansi Lake, a key reservoir along the eastern route of the South-to-North Water Diversion Project. Through field sampling and laboratory simulations, we analyzed the impact of inundation duration, physicochemical properties, and organic matter decomposition on phosphorus release. In Container a (first inundation period), phosphorus was rapidly released at the beginning of inundation, with total phosphorus (TP) in the overlying water increasing from 1.92 mg/L to 2.68 mg/L, and in the interstitial water from 8.45 mg/L to 15.24 mg/L. The second inundation period showed the highest phosphorus release, with TP reaching 3.61 mg/L in the overlying water and 21.51 mg/L in the interstitial water. Inorganic phosphorus dominated the release, with dissolved inorganic phosphorus (DIP) accounting for a higher proportion of TP than dissolved organic phosphorus (DOP). Changes in pH, oxidation-reduction potential (ORP), dissolved oxygen (DO), and total organic carbon (TOC) significantly influenced phosphorus distribution. The decomposition of organic matter during inundation increased dissolved organic matter levels, thereby affecting phosphorus release. These findings provide valuable insights into phosphorus dynamics and highlight the need for integrated management strategies to mitigate internal phosphorus loading and prevent eutrophication in Nansi Lake, offering guidance for water quality management and ecological protection in similar shallow lake systems. Full article